I would also be very interested in seeing the command which produced those
files. It looks like something I would expect to see as a result of
overview building after this patch (and average resampling):
https://trac.osgeo.org/gdal/ticket/2408
~Seth
On Thu, November 20, 2008 10:05 am, Frank Warmerdam wrote:
> Ian Elliott wrote:
>> Hi,
>>>> An error is consistently occurring when I use the nearest neighbour
>> technique to resample an 8-bit paletted image.
>>>> Please see this page for an example:
>>http://projects.exeter.ac.uk/msel/personnel/iae/gdal/>> (The resampling error is shown in image c).
>>>> A possible solution I have discovered is to use 'Majority' resampling,
>> but this is not available in gdal.
>>>> Can anyone suggest why this is happening?
>> Ian,
>> I see the png files on the web site are RGB, and so apparently not the
> original source data. I do not know why nearest neighbour resampling
> would
> give the effect you are seeing. I think you will need to provide details
> on how you accomplished the downsampling (along with the original data)
> for me to say more.
>> There is no majority resampler in gdalwarp or gdal_translate. GDAL 1.6
> does include the MODE resampler for computing overviews with gdaladdo
> which
> I imagine is the same thing as the majority resampler.
>> Best regards,
> --
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up | Frank Warmerdam,
>warmerdam at pobox.com> light and sound - activate the windows | http://pobox.com/~warmerdam> and watch the world go round - Rush | Geospatial Programmer for Rent
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